The Public Test Realm is used by Blizzard to test upcoming patches for both Classic and current versions of World of Warcraft.
All players are eligible to download the PTR, and they are run in English, French, German, and Korean.
There are separate PTR versions for both games so ensure you are downloading the right one you wish to test.
How To Create A PTR Account For World of Warcraft
First, you must register a PTR account, which requires an active subscription.
To do this you need to log in to your Battle.net account and visit the Games & Subscriptions page and select Starter Editions & Public Test Regions to create an account.
Once this has been completed your account will be flagged for PTR access and you can download each version from the Battle.net launcher.
If you have the main games downloaded, the PTR will pull data from there to speed up the process.
PTR testing can vary at times, and will only be accessible for specific times in the leadup towards an upcoming major release.
Not everything will be accessible on the server depending on what needs to be tested, and all progress made on these servers will be lost once the servers are finished for testing.
During the PTR testing, customer support will not be available, so to ensure all issues are resolved players are encouraged to report all bugs and submit reports to the right channels on the World of Warcraft forums.